Tranzyme Pharma, a Durham drug-development company that raised nearly $50 million through an IPO last month, said today that first quarter revenue increased 64 percent.

Revenue for the three-month period that ended March 31 was $2.3 million.

The company reported a net loss of $3.4 million for the quarter, up from a loss of $2.7 million a year ago, due mainly to increased spending on clinical trials.

Tranzyme spent $4.5 million on research and development in the quarter, compared to $2.9 million in the same period a year ago.

Salix Pharmaceuticals reported strong revenue growth in the first quarter, as sales of the company's best-selling drug Xifaxan increased 170 percent from the same period a year ago.

Revenue for the three-month period ended March 31 was $105.9 million, up 140 percent from the same period a year ago. That was slightly below the consensus of $109 million Wall Street analysts estimated.

The company reported net income of $278,000, or 3 cents per share. That was just above the 2 cents per share that analysts expected.

Xifaxan accounted for $80.7 million of the company's revenue in the first quarter.

Salix, which sells drugs to treat gastrointestinal ailments, is one of a handful of drug-development companies in the Triangle with medicines approved for patients' use.

Xifaxan is approved to treat travelers' diarrhea and hepatic encephalopathy, a rare liver condition.

Salix shares dropped 24 percent in a single day in February after the company said it expected regulators to delay approving Xifaxan for treatment of irritable bowel syndrome, a market that the company estimated would be worth billions.

The company said in its earnings release today that it has a June 20 meeting with Food and Drug Administration officials to discuss the agency's IBS ruling.

Salix reiterated its revenue guidance for 2011 of $520 million.

Salix shares closed down 26 cents at $38.09 today. The stock is down 7 percent over the past year.